Nature contents: 15 March 2012

Can't view this email? Click here to view in your browser.     Volume 483 Number 7389      nature •Visit Nature homepage •Subscribe to Nature •View Table of Contents The science that matters. Every week.                       GRANT - Staying on the cutting edge is all about collaboration. That's why Expression Analysis & Illumina have combined forces to help fuel your research — 3 FULLY-FUNDED RNA-Seq Studies and data analysis at no cost to you. Apply on-line today or call 919-405-2248 * 866-293-6094.             Jump to the content that matters to you View Table of Contents ▶ ▼ News & Comment   ▼ Biological Sciences   ▼ Chemical Sciences   ▼ Physical Sciences   ▼ Earth & Environmental Sciences   ▼ Careers & Jobs       This week's highlights     Biological Sciences More Biological sciences ▼   Ancient deuterostome origins of vertebrate brain signalling centres   The vertebrate brain was widely assumed to have a uniquely vertebrate evolutionary history. But now the genetic program that specifies the anterior end of acorn worms - very distant relatives of vertebrates more akin to echinoderms such as starfish - has been found to be an evolutionary link to the line that lead to the complex vertebrate brain.       Physical Sciences More Physical sciences ▼   Creating, moving and merging Dirac points with a Fermi gas in a tunable honeycomb lattice   A tunable system of ultracold quantum gases within an adjustable honeycomb optical lattice has been developed as a model of exotic materials such as topological insulators and graphene.       Physical Sciences More Physical sciences ▼   DNA-based self-assembly of chiral plasmonic nanostructures with tailored optical response   'DNA origami' has been developed as a means of producing plasmonic structures that contain nanoparticles arranged with nanometre precision in nanoscale helices. The optical response of these assemblies can be rationally tuned for handedness, colour and intensity, highlighting the value of DNA origami as a valuable tool for guiding the self-assembly of nanoparticles into materials with desired electric or magnetic properties.                   Cancer drug discovery and development services We offer experience in cytotoxicity and tumor xenograft testing, molecular imaging, 60 human-cell-line panel testing, in vivo evaluation of anticancer compounds and target validation for both in vitro systems and animal models. Learn more here.                 Podcast & Video     In this week's podcast: the quest for the bean without the buzz, what happens when you split the brain in half, and what a brainless worm can tell us about our own grey matter.       Specials - Outlook: Graphene     Owing to its extraordinary electronic and optical properties, this super-strong form of carbon could radically advance technologies ranging from transistors to touch screens to solar cells to bionic implants. But first, materials scientists must figure out how to make large, pristine sheets of graphene economically. ▼ more         News & Comment Read daily news coverage▶ ▲top             THIS WEEK           Editorials                   A Russian renaissance? ▶     Vladimir Putin's promise to increase research spending is welcome — but his country's scientific system needs a complete overhaul.             The shared burden ▶     A proposed change to Germany's constitution is needed for the future health of the universities.             Final say ▶     Ongoing controversy over work at Japan's Tohoku University must be resolved.             World View                   Two nations divided by a common purpose ▶     Plans to replicate Britain's Science Media Centre in the United States are fraught with danger, warns Colin Macilwain.             Seven Days                   Seven days: 9–15 March 2012 ▶     The week in science           NEWS IN FOCUS           Putin promises science boost ▶     But Russian researchers are sceptical of ambitious schemes.             Forecasters look back in time ▶     As the next IPCC assessment nears, scientists use palaeoclimatic data to hone their models.             Spacecraft aims to expose violent hearts of galaxies ▶     Low-cost mission will tap into the unexplored upper reaches of the X-ray spectrum.             Water under pressure ▶     A UN analysis sets out global water-management concerns ahead of Earth Summit.             China's budget backs science ▶     Yet reforms to funding systems and more support for basic research are needed, say scientists.             Japan fails to settle university dispute ▶     Investigations highlight need for a national, independent body to oversee research ethics.             Features                   The split brain: A tale of two halves ▶     Since the 1960s, researchers have been scrutinizing a handful of patients who underwent a radical kind of brain surgery. The cohort has been a boon to neuroscience — but soon it will be gone.             Plant biotechnology: Make it a decaf ▶     The enduring quest for a coffee bean without the buzz.           COMMENT           Drug research: Plug the real brain drain ▶     Martin Schwab and Anita Buchli suggest ways to jump-start the stalled development of therapies for neurological diseases.             Drug research: A plan for mental illness ▶     Thomas R. Insel and Barbara J. Sahakian describe what the next decade of mental-health drug development should look like.             Books and Arts                   Neuroscience: The mind mapped ▶     Robert Stickgold revels in a lively account of a quest to quantify consciousness.             Polar research: Deep-frozen science ▶     Francis Halzen is exhilarated by a trek through stories of research and exploration in Antarctica.             Books in brief ▶             Q&A: The origami geometer ▶     Computer scientist Erik Demaine uses origami to advance computational geometry and create art. His paper sculptures, made with his father, artist Martin Demaine, are now on show at the Japanese American National Museum in Los Angeles, California; from August, the exhibition will tour the United States. He explains the challenges of folding together mathematics and art.             Correspondence                   Animal models: Ads against chimp research criticized Joseph C. LaManna | Turing: Colossus computer revisited Henry Shipley | Turing: Brain model still incomplete David Dalrymple | Turing: Beyond the original concept Christopher Kanan | Alcohol control: Be sparing with international laws Steven J. Hoffman & John-Arne Røttingen           Correction                   Correction ▶                     Biological Sciences ▲top             RESEARCH           Latest Online                   Suppression of the antiviral response by an influenza histone mimic ▶     Ivan Marazzi, Jessica S. Y. Ho, Jaehoon Kim, Balaji Manicassamy, Scott Dewell et al.     The H3N2 influenza virus immunomodulatory protein NS1 carries a sequence that mimics the histone H3 tail; this sequence interferes with the host antiviral response via binding to the cellular regulator of RNA elongation, hPAF1C.             Intrinsic coupling of lagging-strand synthesis to chromatin assembly ▶     Duncan J. Smith & Iestyn Whitehouse     Genome-wide deep sequencing of Okazaki fragments in S. cerevisae reveals a connection between lagging-strand synthesis and chromatin assembly.             Choice-specific sequences in parietal cortex during a virtual-navigation decision task ▶     Christopher D. Harvey, Philip Coen & David W. Tank     The neural circuit dynamics in the mouse posterior parietal cortex are found to involve sequences of neural activation rather than longer-lived sustained neural activity states.             Adaptive radiation of multituberculate mammals before the extinction of dinosaurs ▶     Gregory P. Wilson, Alistair R. Evans, Ian J. Corfe, Peter D. Smits, Mikael Fortelius et al.     Adaptive radiation of Mesozoic-era multituberculate mammals began at least 20 million years before the extinction of non-avian dinosaurs and continued across the Cretaceous–Paleogene boundary—probably as a result of dietary expansion towards herbivory during the ecological rise of angiosperms—and is supported by increases in generic richness and disparity in dental complexity and body size.             Deciphering a neuronal circuit that mediates appetite ▶     Qi Wu, Michael S. Clark & Richard D. Palmiter     Dissection of the neuronal circuit driving feeding behaviour in mice shows that suppression of the parabrachial nucleus protects against aphagia and promotes weight gain, and also that the parabrachial nucleus is an integration hub that bidirectionally modulates feeding and body weight.             Visualizing molecular juggling within a B12-dependent methyltransferase complex ▶     Yan Kung, Nozomi Ando, Tzanko I. Doukov, Leah C. Blasiak, Güneş Bender et al.     The first three-dimensional description of all the protein modules required for the activation, protection and catalytic steps of B12-dependent methyl transfer.             MEGF10 and MEGF11 mediate homotypic interactions required for mosaic spacing of retinal neurons ▶     Jeremy N. Kay, Monica W. Chu & Joshua R. Sanes     The related transmembrane proteins MEGF10 and MEGF11 are shown to have critical roles in the formation of mosaic arrangements in the retina.             Identification and characterization of a bacterial hydrosulphide ion channel ▶     Bryan K. Czyzewski & Da-Neng Wang     A channel for the transport of hydrosulphide ions in Clostridium difficile is identified and shown to be polyspecific, being a member of the formate/nitrite transporter family.             Crystal structure of a concentrative nucleoside transporter from Vibrio cholerae at 2.4 Å ▶     Zachary Lee Johnson, Cheom-Gil Cheong & Seok-Yong Lee     The X-ray crystal structure of a bacterial concentrative nucleoside transporter reveals the overall architecture of this class of transporter and provides a framework for understanding how nucleosides and nucleoside-derived drugs traverse cell membranes.             Tissue factor and PAR1 promote microbiota-induced intestinal vascular remodelling ▶     Christoph Reinhardt, Mattias Bergentall, Thomas U. Greiner, Florence Schaffner, Gunnel Östergren-Lundén et al.     Colonization of germ-free mice with microbiota promotes vascular growth in the small intestine through a mechanism involving tissue factor, PAR1 and Ang1.             The Shigella flexneri effector OspI deamidates UBC13 to dampen the inflammatory response ▶     Takahito Sanada, Minsoo Kim, Hitomi Mimuro, Masato Suzuki, Michinaga Ogawa et al.     Shigella flexneri translocates several virulence factors into host cells during infection; one of these proteins, OspI, is a glutamine deamidase that specifically modifies UBC13, a protein involved in immune signalling.             Structure and mechanism of a glutamate–GABA antiporter ▶     Dan Ma, Peilong Lu, Chuangye Yan, Chao Fan, Ping Yin et al.     The X-ray crystal structure of the glutamate–GABA antiporter GadC is determined, revealing an inward-open conformation and providing insights into mechanism of amino acid antiport that is needed for acid resistance in bacteria.             Articles and Letters                   Ancient deuterostome origins of vertebrate brain signalling centres ▶     Ariel M. Pani, Erin E. Mullarkey, Jochanan Aronowicz, Stavroula Assimacopoulos, Elizabeth A. Grove et al.     Genetic programs homologous to three vertebrate signalling centres are present in the hemichordate Saccoglossus kowalevskii and may be components of a complex, ancient genetic regulatory scaffold for deuterostome body patterning that degenerated in amphioxus and ascidians, but was retained to pattern divergent structures in hemichordates and vertebrates.             Genome-wide structure and organization of eukaryotic pre-initiation complexes ▶     Ho Sung Rhee & B. Franklin Pugh     Ultra-high-resolution mapping of the eukaryotic transcription machinery across the yeast genome reveals several unifying principles of pre-initiation complexes at coding and non-coding genes.             DNA-based self-assembly of chiral plasmonic nanostructures with tailored optical response ▶     Anton Kuzyk, Robert Schreiber, Zhiyuan Fan, Günther Pardatscher, Eva-Maria Roller et al.     Using DNA origami enables the high-yield production of chiral structures containing nanoparticles arranged in helices, with a tunable optical response.             Asymmetric spiroacetalization catalysed by confined Brønsted acids ▶     Ilija Čorić & Benjamin List     Spiroacetals are found in a broad range of biologically active compounds, including small insect pheromones and more complex macrocycles; a confined imidodiphosphoric-acid catalyst is now reported that is able to facilitate the stereoselective synthesis of small, unfunctionalized spiroacetals.             Uncovering the Neoproterozoic carbon cycle ▶     D. T. Johnston, F. A. Macdonald, B. C. Gill, P. F. Hoffman & D. P. Schrag     A quantitative mixing model coupled with new isotopic carbon data from Mongolia, northwest Canada and Namibia reveals that Neoproterozoic era carbonate isotopic anomalies can be accounted for by a primary perturbation to the surface carbon cycle, making other explanations unlikely.             On the difficulty of increasing dental complexity ▶     Enni Harjunmaa, Aki Kallonen, Maria Voutilainen, Keijo Hämäläinen, Marja L. Mikkola et al.     Activation of EDA and activin A signalling, and inhibition of SHH signalling pathways together increase the number of cusps on cultured mouse cheek teeth, showing that a substantial increase in complexity requires multiple changes in developmental regulation.             Coevolution in multidimensional trait space favours escape from parasites and pathogens ▶     R. Tucker Gilman, Scott L. Nuismer & Dwueng-Chwuan Jhwueng     Although pathogens and parasites have short life cycles that let them evolve rapidly, victims can match or overcome exploiter evolution when coevolution involves multiple traits.             Corticostriatal plasticity is necessary for learning intentional neuroprosthetic skills ▶     Aaron C. Koralek, Xin Jin, John D. Long II, Rui M. Costa & Jose M. Carmena     A novel study in rodents suggests that corticostriatal plasticity is necessary for abstract skill learning.             Phase transitions in the assembly of multivalent signalling proteins ▶     Pilong Li, Sudeep Banjade, Hui-Chun Cheng, Soyeon Kim, Baoyu Chen et al.     The mechanisms by which the ångström-scale molecular properties of cells are translated to micrometre-scale macroscopic properties have not been well understood, but this study shows that when multivalent proteins interact with each other, they undergo a switch-like phase separation, which is concomitant with a transition from small complexes to huge polymeric assemblies, as the concentration increases.             A petunia ABC protein controls strigolactone-dependent symbiotic signalling and branching ▶     Tobias Kretzschmar, Wouter Kohlen, Joelle Sasse, Lorenzo Borghi, Markus Schlegel et al.     The Petunia hybrida ABC transporter PDR1 functions in strigolactone export from the roots and is important for regulating symbiosis and axillary branch development.             Goblet cells deliver luminal antigen to CD103+ dendritic cells in the small intestine ▶     Jeremiah R. McDole, Leroy W. Wheeler, Keely G. McDonald, Baomei Wang, Vjollca Konjufca et al.     Goblet cells in the small intestine act as passages delivering small antigens to tolerance-inducing dendritic cells in the lamina propria.             Dysfunction of lipid sensor GPR120 leads to obesity in both mouse and human ▶     Atsuhiko Ichimura, Akira Hirasawa, Odile Poulain-Godefroy, Amélie Bonnefond, Takafumi Hara et al.     Mice deficient in the lipid sensor GPR120 develop obesity, glucose intolerance and fatty liver when fed a high-fat diet, and a loss-of-function variant in the GPR120 gene strongly contributes to increased obesity in human.             Enzymatic catalysis of anti-Baldwin ring closure in polyether biosynthesis ▶     Kinya Hotta, Xi Chen, Robert S. Paton, Atsushi Minami, Hao Li et al.     The X-ray crystal structure of the epoxide hydrolase Lsd19 in complex with its substrate and product analogue is determined, providing insight into a general mechanism of enzyme-catalysed formation of polyether natural products.             An oxygenase that forms and deoxygenates toxic epoxide ▶     Robin Teufel, Thorsten Friedrich & Georg Fuchs     The epoxidase PaaABCE, which converts phenylacetyl-CoA into its ring-1,2-epoxide, is shown to be also able to mediate the NADPH-dependent removal of that epoxide, ensuring that the intracellular concentrations of the toxic epoxide does not exceed a certain ‘acceptable’ concentration.             News & Views                   Organic chemistry: Catalysis in tight spaces ▶     Noah Z. Burns & Eric N. Jacobsen             Developmental biology: A brainy background ▶     Henry Gee             Genetics: Broken giant linked to heart failure ▶     Elizabeth M. McNally             Neuroscience: How brains learn to control machines ▶     David T. Blake             Biochemistry: Favouring the unfavoured ▶     David E. Cane             Gene expression: Transcription initiation unwrapped ▶     Stephen Buratowski             Virology: Influenza's tale of tails ▶     Alexei L. Krasnoselsky & Michael G. Katze             Corrigendum                   Corrigendum: Functional complementation between FADD and RIP1 in embryos and lymphocytes ▶     Haibing Zhang, Xiaohui Zhou, Thomas McQuade, Jinghe Li, Francis Ka-Ming Chan et al.             Research Highlights                   Plant evolution: Outback palms were planted | Physiology: Sawfish snouts sense and stab | Organic electronics: Sterilization-ready transistors | Cancer genetics: Many genomes in one tumour | Immunology: Controlling natural killers | Palaeoecology: What killed the big beasts? | Genetics: James Crow on sabotaging sperm         NEWS & COMMENT           Water under pressure | The split brain: A tale of two halves | Plant biotechnology: Make it a decaf | Drug research: Plug the real brain drain | Drug research: A plan for mental illness | Neuroscience: The mind mapped | Books in brief | Animal models: Ads against chimp research criticized Joseph C. LaManna | Turing: Brain model still incomplete David Dalrymple           CAREERS           Turning point: Sean Bendall             More Biological Sciences ▶                         The New York Stem Cell Foundation requests applications from early career investigators in the US, Canada and the UK to cultivate innovative projects exploring fundamental areas of developmental, cellular, cognitive, and behavioral neuroscience. Proposals need not be related to stem cells. The award provides $1.5M USD over 5 years. Closing date March 30th, 2012.               Chemical Sciences ▲top             RESEARCH           Latest Online                   Suppression of the antiviral response by an influenza histone mimic ▶     Ivan Marazzi, Jessica S. Y. Ho, Jaehoon Kim, Balaji Manicassamy, Scott Dewell et al.     The H3N2 influenza virus immunomodulatory protein NS1 carries a sequence that mimics the histone H3 tail; this sequence interferes with the host antiviral response via binding to the cellular regulator of RNA elongation, hPAF1C.             Intrinsic coupling of lagging-strand synthesis to chromatin assembly ▶     Duncan J. Smith & Iestyn Whitehouse     Genome-wide deep sequencing of Okazaki fragments in S. cerevisae reveals a connection between lagging-strand synthesis and chromatin assembly.             Visualizing molecular juggling within a B12-dependent methyltransferase complex ▶     Yan Kung, Nozomi Ando, Tzanko I. Doukov, Leah C. Blasiak, Güneş Bender et al.     The first three-dimensional description of all the protein modules required for the activation, protection and catalytic steps of B12-dependent methyl transfer.             Identification and characterization of a bacterial hydrosulphide ion channel ▶     Bryan K. Czyzewski & Da-Neng Wang     A channel for the transport of hydrosulphide ions in Clostridium difficile is identified and shown to be polyspecific, being a member of the formate/nitrite transporter family.             Crystal structure of a concentrative nucleoside transporter from Vibrio cholerae at 2.4 Å ▶     Zachary Lee Johnson, Cheom-Gil Cheong & Seok-Yong Lee     The X-ray crystal structure of a bacterial concentrative nucleoside transporter reveals the overall architecture of this class of transporter and provides a framework for understanding how nucleosides and nucleoside-derived drugs traverse cell membranes.             The Shigella flexneri effector OspI deamidates UBC13 to dampen the inflammatory response ▶     Takahito Sanada, Minsoo Kim, Hitomi Mimuro, Masato Suzuki, Michinaga Ogawa et al.     Shigella flexneri translocates several virulence factors into host cells during infection; one of these proteins, OspI, is a glutamine deamidase that specifically modifies UBC13, a protein involved in immune signalling.             Structure and mechanism of a glutamate–GABA antiporter ▶     Dan Ma, Peilong Lu, Chuangye Yan, Chao Fan, Ping Yin et al.     The X-ray crystal structure of the glutamate–GABA antiporter GadC is determined, revealing an inward-open conformation and providing insights into mechanism of amino acid antiport that is needed for acid resistance in bacteria.             Articles and Letters                   Genome-wide structure and organization of eukaryotic pre-initiation complexes ▶     Ho Sung Rhee & B. Franklin Pugh     Ultra-high-resolution mapping of the eukaryotic transcription machinery across the yeast genome reveals several unifying principles of pre-initiation complexes at coding and non-coding genes.             Asymmetric spiroacetalization catalysed by confined Brønsted acids ▶     Ilija Čorić & Benjamin List     Spiroacetals are found in a broad range of biologically active compounds, including small insect pheromones and more complex macrocycles; a confined imidodiphosphoric-acid catalyst is now reported that is able to facilitate the stereoselective synthesis of small, unfunctionalized spiroacetals.             Phase transitions in the assembly of multivalent signalling proteins ▶     Pilong Li, Sudeep Banjade, Hui-Chun Cheng, Soyeon Kim, Baoyu Chen et al.     The mechanisms by which the ångström-scale molecular properties of cells are translated to micrometre-scale macroscopic properties have not been well understood, but this study shows that when multivalent proteins interact with each other, they undergo a switch-like phase separation, which is concomitant with a transition from small complexes to huge polymeric assemblies, as the concentration increases.             Enzymatic catalysis of anti-Baldwin ring closure in polyether biosynthesis ▶     Kinya Hotta, Xi Chen, Robert S. Paton, Atsushi Minami, Hao Li et al.     The X-ray crystal structure of the epoxide hydrolase Lsd19 in complex with its substrate and product analogue is determined, providing insight into a general mechanism of enzyme-catalysed formation of polyether natural products.             An oxygenase that forms and deoxygenates toxic epoxide ▶     Robin Teufel, Thorsten Friedrich & Georg Fuchs     The epoxidase PaaABCE, which converts phenylacetyl-CoA into its ring-1,2-epoxide, is shown to be also able to mediate the NADPH-dependent removal of that epoxide, ensuring that the intracellular concentrations of the toxic epoxide does not exceed a certain ‘acceptable’ concentration.             News & Views                   Organic chemistry: Catalysis in tight spaces ▶     Noah Z. Burns & Eric N. Jacobsen             Biochemistry: Favouring the unfavoured ▶     David E. Cane             Gene expression: Transcription initiation unwrapped ▶     Stephen Buratowski           NEWS & COMMENT           Japan fails to settle university dispute | Books in brief             More Chemical Sciences ▶               Physical Sciences ▲top             RESEARCH           Latest Online                   Collapse of polar ice sheets during the stage 11 interglacial ▶     Maureen E. Raymo & Jerry X. Mitrovica     The magnitude of sea level rise during marine isotope stage 11 (about 400,000 years ago) is shown to have been probably only 6 to 13 metres, in contrast to some earlier estimates of up to 20 metres.             Articles and Letters                   Creating, moving and merging Dirac points with a Fermi gas in a tunable honeycomb lattice ▶     Leticia Tarruell, Daniel Greif, Thomas Uehlinger, Gregor Jotzu & Tilman Esslinger     A tunable optical lattice is used to engineer massless and massive Dirac fermions and realize the topological transition at which two Dirac points merge and annihilate each other.             Designer Dirac fermions and topological phases in molecular graphene ▶     Kenjiro K. Gomes, Warren Mar, Wonhee Ko, Francisco Guinea & Hari C. Manoharan     The formation of massless Dirac fermions is demonstrated in a highly tunable molecular graphene lattice, and particular distortions of the lattice are shown to endow the fermions with mass or engage the fermions with artificial electric and magnetic fields.             DNA-based self-assembly of chiral plasmonic nanostructures with tailored optical response ▶     Anton Kuzyk, Robert Schreiber, Zhiyuan Fan, Günther Pardatscher, Eva-Maria Roller et al.     Using DNA origami enables the high-yield production of chiral structures containing nanoparticles arranged in helices, with a tunable optical response.             Uncovering the Neoproterozoic carbon cycle ▶     D. T. Johnston, F. A. Macdonald, B. C. Gill, P. F. Hoffman & D. P. Schrag     A quantitative mixing model coupled with new isotopic carbon data from Mongolia, northwest Canada and Namibia reveals that Neoproterozoic era carbonate isotopic anomalies can be accounted for by a primary perturbation to the surface carbon cycle, making other explanations unlikely.             Phase transitions in the assembly of multivalent signalling proteins ▶     Pilong Li, Sudeep Banjade, Hui-Chun Cheng, Soyeon Kim, Baoyu Chen et al.     The mechanisms by which the ångström-scale molecular properties of cells are translated to micrometre-scale macroscopic properties have not been well understood, but this study shows that when multivalent proteins interact with each other, they undergo a switch-like phase separation, which is concomitant with a transition from small complexes to huge polymeric assemblies, as the concentration increases.             News & Views                   Electronics: Inside story of ferroelectric memories ▶     Vincent Garcia & Manuel Bibes             Condensed-matter physics: A duo of graphene mimics ▶     Jonathan Simon & Markus Greiner             Research Highlights                   Organic electronics: Sterilization-ready transistors | Palaeoecology: What killed the big beasts? | Materials: A new way to 3D shapes         NEWS & COMMENT           Seven days: 9–15 March 2012 | Forecasters look back in time | Spacecraft aims to expose violent hearts of galaxies | Japan fails to settle university dispute | Polar research: Deep-frozen science | Books in brief | Q&A: The origami geometer | Turing: Colossus computer revisited Henry Shipley | Turing: Brain model still incomplete David Dalrymple | Turing: Beyond the original concept Christopher Kanan             More Physical Sciences ▶               Earth & Environmental Sciences ▲top             RESEARCH           Latest Online                   Adaptive radiation of multituberculate mammals before the extinction of dinosaurs ▶     Gregory P. Wilson, Alistair R. Evans, Ian J. Corfe, Peter D. Smits, Mikael Fortelius et al.     Adaptive radiation of Mesozoic-era multituberculate mammals began at least 20 million years before the extinction of non-avian dinosaurs and continued across the Cretaceous–Paleogene boundary—probably as a result of dietary expansion towards herbivory during the ecological rise of angiosperms—and is supported by increases in generic richness and disparity in dental complexity and body size.             Collapse of polar ice sheets during the stage 11 interglacial ▶     Maureen E. Raymo & Jerry X. Mitrovica     The magnitude of sea level rise during marine isotope stage 11 (about 400,000 years ago) is shown to have been probably only 6 to 13 metres, in contrast to some earlier estimates of up to 20 metres.             Articles and Letters                   Uncovering the Neoproterozoic carbon cycle ▶     D. T. Johnston, F. A. Macdonald, B. C. Gill, P. F. Hoffman & D. P. Schrag     A quantitative mixing model coupled with new isotopic carbon data from Mongolia, northwest Canada and Namibia reveals that Neoproterozoic era carbonate isotopic anomalies can be accounted for by a primary perturbation to the surface carbon cycle, making other explanations unlikely.             Research Highlights                   Geophysics: Rain slows seismic waves | Planetary science: Venusian hot flow anomalies | Palaeoecology: What killed the big beasts?         NEWS & COMMENT           Forecasters look back in time | Water under pressure | Polar research: Deep-frozen science           CAREERS           Environment: Toxic effects             More Earth & Environmental Sciences ▶               Specials - Nature Outlook: GrapheneFree Access ▲top               Graphene ▶     Herb Brody              Materials science: Super carbon ▶     Graphene is phenomenally strong, thin, flexible, transparent and conductive — and applications beckon.              Production: Beyond sticky tape ▶     Flecks of graphene are easy to make. But producing sheets of pristine, electronics-quality material is another matter.              Electronics: Back to analogue ▶     Trying to shoehorn graphene into a digital circuit isn't working. But there may be another potential path to glory.              Bioelectronics: The bionic material ▶     Graphene could make an ideal basis for a medical repair kit.              Come into the light ▶     Transparency across the spectrum combined with electronic prowess makes graphene an ideal photonic material.              Q&A: Taking charge ▶     Nature Outlook talks to the first director of the MIT's Centre for Graphene Devices and Systems, which was created in July 2011 to foster collaboration among academic, industrial and government groups studying this form of carbon.              Perspective: A means to an end ▶     Exploring graphene's chemical properties reveals a world of potential away from the purely two-dimensional, says Rodney Ruoff.              Material history: Learning from silicon ▶     Silicon is more than an incumbent technology competing with graphene — it also has a history researchers should remember.          Sponsors                     Nature Outlook: Lenses on Biology In this special edition of Nature Outlook, five top scientists explain how research in their specialties - cancer, climate change, stem cells, oceanography and synthetic biology - has changed our lives. Access the Outlook free online for six months. Produced in partnership with Nature Education.               Careers & Jobs ▲top               Environment: Toxic effects ▶     Environmental concerns and more stringent laws are providing opportunities for environmental toxicologists.                   Turning point: Sean Bendall ▶     Sean Bendall, a postdoctoral fellow in stem-cell and cancer biology at Stanford University in Palo Alto, California, won the Dale F. 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